Water On The Roof For Cooling

At its lowest tech a roof misting system can be little more than a garden hose set to the mist setting and aimed across the roof.

Water on the roof for cooling.

This cools the roof which acts as a heat sink and absorbs heat from the interior of the building. Also called an evaporative cooling system a roof misting system lowers surface temperatures by spraying an extremely small amount of water across the roof allowing the water to cool the roof as it evaporates. Ambient indoor temperature is approx. Yes you can spray your roof to help cool it down but that will only cool the shingles for a short time and be a large waste of water.

One study indicates that water use is around 100 gallons per day per 1000 sqft of roof area. An evaporating layer of water on the roof approaches a wet bulb temperature of 12 c a typical roof reaches 60 100 c mitigating the albedo effect. There should be 1 square foot of vent for every 300 square feet of floor space. A more refined method involves insulating the pond during the daytime to prevent solar gain.

Cooling with liquid water running off from a sprinkler is not efficient but evaporative cooling from a small amount of water like a periodic sprinkle is very efficient. As water evaporates from the pond heat is consumed. Areas where water is in short supply. Prototype for a evaporative roof for radiant cooling cherry valley ca usa reconsidering comfort.

In the simplest form this involves placing a pond on the building roof. 50 radiant heat from surface radiation and 50 air temperature. These systems provide cooling by spraying the water evaporates and cools the surface.